AlgART Libraries is a collection of Java libraries, supporting generalized smart arrays and matrices with elements of any types, including a wide set of of 2D, 3D, and multidimensional image processing and other algorithms. Main features: 64-bit long int indexes, a memory model concept (allowing storing data in different schemes from RAM to mapped disk files), wide usage of lazy evaluations, built-in multi-threading optimization for multi-core processors, etc.

JDAL is a Java library which aims to help developers make database applications easily using
Spring Framework and Hibernate,
JPA,
or IBatis ORMs.
It supports generic DAOs and ready-to-use UI Components with server-side pagination and sorting.

gedcom4j is a Java library for loading (parsing) and saving GEDCOM 5.5 or 5.5.1 files to/from a Java object hierarchy, which can be manipulated by your code as you see fit. Please note that gedcom4j is not an application. It is a library for parsing, manipulating, and writing GEDCOM data in your own programs.

JMapper-Framework allows you to pass data from one Java Bean to another dynamically with annotations and/or XML. You can create and enrich target objects, apply specific logic to the mapping, automatically manage the XML file, implement the 1-to-N and N-to-1 relationships, implement explicit conversions, apply inherited configurations, and more.

Genson is a lightweight Java library for doing conversion between JSON and Java. It provides full databinding and Java generics support. Genson's main goals are to come with rich features out of the box, great performance and scalability, and easy ways to add new features.

Snippetory is a general Java template engine based on passive templates. In passive templates, template code and logic are clearly separated from each other. The templates contains very simple mark up. By removing logic, templates are directly accessible, fully parametrized, and free of context, and can easily be reused. Navigation, code competition, and structuring of the code with methods and classes are supported.

jRapidRPC is a Java RPC library that allows you to create client-server applications that talk in objects. It is small, fast, and extensible. Its smallness helps you learn how to use the library quickly. jRapidRPC is fast due to its compact size and lack of complexity. Also, it uses the ProtoStuff serializer by default. jRapidRPC's extensibility allows you to can write a new client-server or a new serializer.

Athena Framework for Java is a full fledged enterprise object-relational mapping (ORM) framework that employs metadata as mapping configuration. It greatly simplifies Java Web application development by removing the requirement of manual mapping and manual database schema updating. In addition to features like Java object persistence, powerful EJBQL querying execution, and comprehensive code generation, Athena has built-in support for multi-tenancy, which enables developers to build cloud applications easily. Athena can be easily integrated with other libraries like Struts or Spring to provide full stacks of service.